1. Field of the Invention
The present invention relates to hand-held communication devices, and more particularly, to a hand-held communication device with a rotatable antenna
2. Description of the Prior Art
In recent years, the popularity of the hand-held communication devices continues to rise because of the development and progress of communications techniques. Many people in modern society have at least one hand-held communication device. So-called hand-held communication devices include a large of variety of devices, such as cellular phones and personal data assistants. In spite of these various kinds of the hand-held communication devices having different internal parts corresponding to different functions provided, they basically include an antenna for receiving and transmitting a radio frequency signal, and a transceiver for handling the radio frequency signal. Good radio signal transceiving quality is very important with regard to all kinds of communication devices; therefore, antennas play a very significant role. If an antenna can only receive a weak radio frequency signal from its corresponding direction, then the signal will not be strong enough to be processed by the transceiver. In this way, the communication device will lose its most basic functionality, communication, and other various functions it possesses will become less useful.
Take a hand-held communication device with a global positioning system, for example. Because the antenna applied to such a communication device is a highly directional antenna, meaning that a user needs to point the housing in which the antenna located toward to the signal source for receiving a satellite signal, the prior art includes a rotation axle between the communication device itself and the antenna to improve the reception range of the antenna. The rotation axle provided by the prior art lets the user adjust the direction of the antenna by rotation in two-dimensional space to optimize the strength of the satellite signal. Please refer to FIG. 1 showing a block diagram of a hand-held communication device 10 with a global position system according to the prior art. Such communication device 10 includes a first housing 12, a processor 13 installed inside the first housing 12 for handling data, a transceiver 15 installed inside the first housing 12 and connected to the processor 13 for handling a radio frequency signal, an LCD panel 8 installed inside the first housing 12 for displaying data, a second housing 14, an antenna 11 installed inside the second housing 14, a signal line 17 connected to the antenna 11 and the transceiver 15 for transmitting a radio frequency signal, and a rotation axle 16 connected to the first housing 12 in a rotatable manner. One end of the second housing 14 is fixed to the rotation axle 16 so that the second housing 14 can be rotated with respect to the first housing 12.
The antenna of the communication device above can only rotate in two dimensions, and thus, the range of radio frequency signal reception is limited. Please refer to FIG. 2, which is a block diagram of the hand-held communication device 10 when the second housing 14 is rotated zero degrees. FIG. 3 is a block diagram of the hand-held communication device 10 when the second housing 14 is rotated 180 degrees. Arrows 18 and 22 represent the normal direction of the antenna 11. When the second housing 14 is positioned as shown in FIG. 2 and FIG. 3 and the direction of the satellite signal is parallel with arrows 18, the radio frequency signal reception of the antenna 11 is optimized. However, when the direction transmitted from the satellite signal follows arrows 20 or arrows 21, because arrows 18 and 22 are orthogonal with arrows 20 and 21, the antenna will not receive the satellite signals. Please refer to FIG. 4, which is a block diagram of the hand-held communication device 10 when the second housing 14 is rotated 90 degrees. Arrow 24 is the normal direction of the antenna 11. In this case, the radio frequency signal reception of the antenna 11 can be optimized because arrow 24 is parallel with arrow 21. However, the antenna 11 still cannot receive the satellite signal transmitted from arrow 20 because arrow 20 is orthogonal to arrow 24.
Based on the observations above, it is known that the rotation axle 16 added to the hand-held communication device can only let the antenna do two-dimensional rotation. In this way, a satellite signal transmitted from some directions (e.g. arrow 20) cannot be received unless the user changes the position of the hand-held communication device 10. However, sometimes the user cannot change the position of the hand-held communication device for some reason, so the radio frequency signal reception of the antenna 11 cannot be optimized.